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Larry Ruble
13 Posts |
 Posted - 01/12/2004 : 3:57:51 PM
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I COMPLETED MY 3 METER MANTIS 1/11/04 AND CAN'T WAIT TO FLY IT.
I AM CONCERNED AB0UT THE WAY I INSTALLED THE ALUMINUM CONTROL HORNS JEFF NEWCUM SUGGESTED IN A DIAGRAM HE HAS ON THIS WEBSITE.
I CA'D THE CONTROL HORN TO THE UNDERSIDE OF THE TOP OF THE RUDDERVATOR AND THEN FILLED A CAVITY AROUND IT WITH 5 MINUTE EXPOXY.
WOULD IT BE A GOOD IDEA TO LAY A SMALL PIECE OF KEVLAR OR GLASS OVER THE CONTROL HORN AND THE TOP AND BOTTOM OF THE CONTROL SURFACE?
THANKS FOR SOME FEEDBACK. |
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Phil Barnes
100 Posts |
Posted - 01/12/2004 : 4:43:38 PM
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| I looked at Jeff Newcum's diagram under the "building the Aegea glider" topic heading. I assume you made the control horns as he shows in the diagram. The diagram shows a part of the horn material bent over at an angle to form an ear which is embedded in the ruddervator. From your post, it sounds like you have that ear glued directly to the top skin of the ruddervator and that the cavity that is left between the ear and the bottom skin of the ruddervator is filled with epoxy. That sounds like a good system. I think you could very easily add a piece of glass that covers the leading edge of the ruddervator ahead of the horn's ear and which wraps over to the bottom of the ruddervator. The glass would be attached with epoxy. This would be easy and would not harm the cosmetic apearance and would add a great deal of strength. I don't think it is likely that the horn would pop off from normal use without the glass, but the glass would add insurance and make that area more resistant to damage from accidents. |
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Phil Barnes
100 Posts |
Posted - 01/12/2004 : 4:58:00 PM
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Here is another way to make V tail control horns. I'll do my best to describe it. I have not made a model this way yet, so I don't have any pictures.
You can use a 4-40 threaded rod to make the horn. You want the type of 4-40 rod that is mostly plain rod but with threads on the last inch or so. What you do is bend the rod such that the threaded portion of the rod points straight down vertically from the root end end of the ruddervator at the leading edge. A 4-40 ball link is threaded on to the end of this rod and attaches to the the nylon socket on the end of the pushrod. The rod is bent such that it goes into the ruddervator along the leading edge of the ruddervator for about an inch and a half. Then it makes a ninety degree bend and goes into the ruddervator a little bit. This rod/horn is epoxied into place and a little piece of glass can be wrapped over the leading edge of the ruddervator to secure it.
You must also cut off enough of the threads on the end of the 4-40 rod so that you will not have to bend the rod where there are threads. The rod will break if you try to bend it where the threads are.
This is hard to describe without a picture but is really simple. It is just a 4-40 rod with two bends and a ball link on the end.
If anybody makes one this way, pictures would be apreciated,.
Phil |
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F3jeb
103 Posts |
Posted - 01/12/2004 : 8:30:49 PM
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I set mine up as described by Jeff, at Fritz’, and later found they buckled right where the insertion ended (marked in red below), so I had to add some Kevlar at the crease for reinforcement. I also had some reservations about the metal being so soft.
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My old K2 had a very clever tail horns system, here is a picture of it, I’ll try to look for a picture of one assembled.
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Jose |
Edited by - F3jeb on 05/25/2004 7:53:18 PM |
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F3jeb
103 Posts |
Posted - 01/12/2004 : 8:54:59 PM
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Ok, this is a tail from another euro-plane and the K2 works exactly the same with the very stiff piece of wire you see above. There was a solid strip of hard wood in the tail where the wire would insert and rest.
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Phil Barnes
100 Posts |
Posted - 01/13/2004 : 07:53:55 AM
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Jose's last two pictures are exactly what the 4-40 threaded rods would look like. The only difference would be the actual ball joint on the end. They sell a 4-40 ball joint with a female socket that would just thread over the end of the 4-40 rod, it's called a "bolt on ball link". I bought some a long time ago from Tower Hobbies. They were Dubro part number 180 or Tower Hobbies part number DUBQ1700. I couldn't find them in the current Tower Hobbies catalog, unfortunately.
Phil |
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VTAIL ALUMINUM CONTROL HORNS
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